Piezoelectric fan driving device

Abstract

The invention relates to a piezoelectric fan driving device comprising: a piezoelectric fan and a driving unit, wherein the piezoelectric fan comprises a connecting piece, two piezoelectric elements and at least one one-way air flowing piece. The connecting piece has an opening and two end surfaces. The two piezoelectric elements are fixed on the two end surfaces, and the connecting piece and two piezoelectric elements surround to form a cavity, one of the two piezoelectric elements having a through hole connecting to the cavity. The one-way air flowing piece connects the through hole. The driving unit electrically connects with the two piezoelectric elements to convert a DC power to an AC power, and the two piezoelectric elements are driven by the AC power.

What is claimed is: 
     
         1 . A piezoelectric fan driving device comprising:
 a piezoelectric fan and a driving unit,   wherein the piezoelectric fan comprises:   a connecting piece having an opening and two end surfaces;   two piezoelectric elements fixed on the two end surfaces, and the connecting piece and two piezoelectric elements surrounding to form a cavity, one of the two piezoelectric elements having a through hole connecting to the cavity; and   at least one one-way air flowing piece connecting to the through hole, and   the driving unit electrically connects with the two piezoelectric elements to convert a DC power to an AC power, and the two piezoelectric elements are driven by the AC power.   
     
     
         2 . The piezoelectric fan driving device of  claim 1 , wherein the one-way air flowing piece is a one-way limiting diaphragm. 
     
     
         3 . The piezoelectric fan driving device of  claim 1 , wherein the one-way air flowing piece is a one-way valve. 
     
     
         4 . The piezoelectric fan driving device of  claim 1 , wherein each the two piezoelectric elements comprises a membrane and a piezoelectric sheet, wherein the membrane is fixed on the two end surfaces of the connecting piece, and the piezoelectric sheet is fixed on a central position of the membrane, and the through hole is provided on the membrane or the piezoelectric sheet. 
     
     
         5 . The piezoelectric fan driving device of  claim 4 , wherein the membrane is made of metallic sheet or plastic sheet. 
     
     
         6 . The piezoelectric fan driving device of  claim 1 , wherein the connecting piece has a horizontal rod and two vertical rods extending from two ends of the horizontal rod, and the opening is formed between the two vertical rods, and the two end surfaces are respectively formed on an upper surface and a lower surface of the horizontal rod and the two vertical rods. 
     
     
         7 . The piezoelectric fan driving device of  claim 1 , wherein the connecting piece is U-shape. 
     
     
         8 . The piezoelectric fan driving device of  claim 1 , wherein the connecting piece is a compressive elastomer. 
     
     
         9 . The piezoelectric fan driving device of  claim 1 , wherein the connecting piece is made of rubber or silicone material. 
     
     
         10 . The piezoelectric fan driving device of  claim 1 , wherein the connecting piece has a recess toward inside between the two end surfaces, and the recess has a thickness less than a thickness of the connecting piece. 
     
     
         11 . The piezoelectric fan driving device of  claim 1 , wherein the connecting piece decreases a thickness gradually from two end surfaces to the recess so that the connecting piece has a section being V-shape or U-shape. 
     
     
         12 . The piezoelectric fan driving device of  claim 1 , wherein the driving unit comprises:
 a power converter for converting the DC power into AC power; and   a power amplifier connecting with the power converter and two piezoelectric elements, amplifying the AC power output from the power converter to drive the two piezoelectric elements.